Flow distributor of an electrically heated cigarette smoking system

ABSTRACT

A heater fixture for use in an electrically heated cigarette smoking system having a source of electrical energy for heating a cigarette includes an inner wall or barrel having at least one opening through the inner wall extending from an outer peripheral surface to an inner surface of the inner wall, and at least one flow distributing element positioned within the at least one opening and extending inwardly from the inner surface. The flow distributing element or elements are provided with a plurality of openings that are in fluid communication with an interior of the heater.

FIELD OF THE INVENTION

The present invention relates to a heater for use in an electricallyheated cigarette smoking system.

BACKGROUND OF THE INVENTION

Previously known conventional lit cigarettes deliver flavor and aroma tothe user as a result of combustion of tobacco. A mass of combustiblematerial, primarily tobacco, is oxidized as the result of applied heatwith typical combustion temperatures in a conventional cigarette beingin excess of 800 degrees Celsius during puffing.

Lit-end cigarettes have some perceived drawbacks associated with them.Among them is the production of side stream smoke during smolderingbetween puffs, which may be objectionable to some non-smokers. Also,once lit, lit-end cigarettes must be fully consumed or discarded.Relighting a lit-end cigarette is possible but is usually anunattractive prospect for subjective reasons related to flavor, tasteand odor.

Electrical smoking systems including electrically powered lighters andspecially designed cigarettes that are adapted to cooperate with thelighters are disclosed in several commonly assigned U.S. patents,including U.S. Pat. Nos. 5,591,368, 5,878,752, 5,093,894, 5,225,498,5,060,671, 5,095,921, 5,388,594 and 5,499,636, each of which isincorporated herein by reference.

In an embodiment of the lighter of U.S. Pat. No. 5,878,752, as shown inFIGS. 1 and 2, the smoking system 21 includes a cylindrical cigarette 23and a reusable, hand-held lighter 25. The cigarette 23 is adapted to beinserted and removed from an orifice 27 at a front end 29 of the lighter25. The cigarette 23 is disposed of after one or more puff cycles. Thelighter 25 is preferably disposed of after a greater number of puffcycles than the cigarette 23. The lighter 25 includes a housing 31 andhas front and rear portions 33 and 35. A power source 37 for supplyingenergy to heater elements 120 for heating the cigarette 23 is preferablydisposed in the rear portion 35 of the lighter 25. The rear portion 35is preferably adapted to be easily opened and closed, such as withscrews or with snap-fit components, to facilitate replacement of thepower source 37. The front portion 33 preferably houses heater elementsand circuitry in electrical communication with a power source 37 in therear portion 35. The housing 31 is preferably adapted to fit comfortablyin the hand of a smoker and, in a presently preferred embodiment, hasoverall dimensions of approximately 10.7 cm×3.8 cm×1.5 cm. The powersource 37 is sized to provide sufficient power for heater elements thatheat the cigarette 23. The power source 37 is preferably replaceable andrechargeable and may include devices such as a capacitor, or morepreferably, a battery. A substantially cylindrical heater fixture 39 forheating the cigarette 23, and, preferably, for holding the cigarette inplace relative to the lighter 25, and electrical control circuitry 41for delivering a predetermined amount of energy from the power source 37to cigarette heater elements 120 of the heater fixture 39, arepreferably disposed in the front 33 of the lighter.

The plurality of metallic heaters 120 are disposed in a configurationthat slidingly receives a tobacco rod portion of a cigarette. One of themany advantages of such a smoking system is the reusability of thelighter for numerous cigarettes. In the heater fixture disclosed in U.S.Pat. No. 5,878,752 and shown in FIGS. 1 and 2, a cigarette would beinserted through the tapered opening at the right side of FIG. 2 into asubstantially cylindrical space of the cigarette heater fixture definedby a ring-shaped cap 83 having an open end for receiving the cigarette,a cylindrical air channel sleeve 87, an outer sleeve 84, a heaterassembly including the heater blades 120, and electrically conductivepins or leads 104A and 104B. The spacer 49 stops the cigarette in adesired position in the cigarette heater fixture such that the heaterblades 120 are disposed in a snug fit around the outer circumference ofthe cigarette. The heater fixture disclosed in U.S. Pat. No. 5,878,752shows an air channel sleeve 87 through which air can flow axially inorder to reach the point where the heater blades 120 contact thecigarette. Gaps 125, 126 and 130 can provide pathways for the air to bedrawn into contact with the inserted cigarettes.

SUMMARY OF THE INVENTION

An embodiment according to the present invention provides a desirableimprovement in air flow distribution to heater blades of an electricalsmoking system, which results in an increase of the total aerosoldelivery of the system.

In a modification of the heater disclosed in U.S. Pat. No. 5,878,752,the air flow channel sleeve 87 can be eliminated and air directed to theheater blades through radial holes in the sleeve 200. Air can reach theoutside of sleeve 200 after passing through an opening or openings inthe housing 31 of the lighter 25. Although not shown in FIG. 1, suchopenings would typically be provided through the housing 31 at the front33 of the lighter 25. It has been discovered that side holes through thesleeve surrounding the heater blades may result in channeling of the airflow over a limited area of the heater. With limited air flow to theheater blades and the cigarette, the pyrolysis of the cigarette is alsolimited and the total particulate matter produced in the generatedaerosol is restricted. Accordingly, limitations in the air flow to theheater blades can result in the heater failing to produce sufficientaerosol to provide a smoker with the desired flavors and aromas.

A heater fixture for use in a smoking system having a source ofelectrical energy for heating a cigarette according to an embodiment ofthe invention includes an inner wall, said inner wall having at leastone opening through the wall extending from an outer peripheral surfaceto an inner surface of the wall, and at least one flow distributingelement positioned within said at least one opening and extendinginwardly from the inner surface. The at least one flow distributingelement includes a plurality of openings that are in fluid communicationwith an interior of the heater fixture. A plurality of heater elementsare arranged in the interior of the heater fixture within the innerwall, and fit snugly around the outer circumference of a cigaretteinserted into the heater fixture. The openings from the flowdistributing element into the interior of the heater fixture extendradially outward from the central axis of each flow distributing elementand ensure that the air flow will be mixed within the heater fixture asthe air is directed in different directions through the holes from theflow distributing element.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electrical lighter.

FIG. 2 illustrates a side cross-sectional view of a heater fixturesurrounded by an inner barrel or sleeve and associated heater element.

FIG. 3A illustrates a side cross-sectional view through a flowdistributing element according to an embodiment of the invention.

FIG. 3B is a cross-sectional view taken in the direction of arrows A-Ain FIG. 3A of a flow distributing element according to an embodiment ofthe invention.

FIG. 4 illustrates an inner barrel or sleeve for the heater in anelectrically heated cigarette smoking system and having two side holesthrough the barrel to provide air flow into the heater.

FIG. 5 and the enlarged view in FIG. 5A illustrate the inner barrel ofFIG. 2 modified to include two flow distributing elements according toan embodiment of the invention placed through the side holes.

FIG. 6 illustrates a side cross-sectional view of an inner barrel for aheater having flow distributing elements according to an embodiment ofthe invention and an outer barrel having openings positioned radiallyoutward from the flow distributing elements.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A heater fixture of an electrical smoking system having improved airflow is described below. Electrically heated cigarette smoking systemsare described in greater detail in U.S. Pat. Nos. 5,388,594 and5,878,752, which are hereby incorporated by reference in theirentireties. The fixture used in the electrically heated cigarettesmoking systems described in the above patents is shown in FIGS. 1 and 2of the present application. A specially designed cigarette is adapted tobe inserted in and removed from an orifice 27 at a front end of theheater fixture 39. The heater fixture 39 is preferably substantiallycylindrical, and holds a cigarette in place relative to the electricallyheated cigarette smoking system in which the heater fixture issupported. Electrical control circuitry can also be provided within theelectrically heated cigarette smoking system for delivering apredetermined amount of energy from a power source to the cigaretteheater elements 120, shown in FIG. 2. A generally circular, terminal endhub 110 is fixed, e.g., welded, to be disposed within the interior ofthe cigarette heater fixture 39, e.g., is fixed to a spacer 49, as shownin FIG. 2.

The heater fixture 39 includes a plurality of radially spaced heaterblades 120 supported to extend from the hub 110, as shown in FIG. 2. Theheater blades 120 are individually energized by a power source under thecontrol of electrical circuitry (not shown).

The heater elements 120 can comprise any suitable heater element forheating tobacco to evolve tobacco flavors. For example, the heatingsystem can comprise any of the resistance and induction heating systemsdisclosed in the above-referenced patents.

A cigarette is inserted in the orifice 27 of the heater fixture 39, andinto a substantially cylindrical space of the heater fixture 39 definedby a ring-shaped cap 83 having an open end for receiving the cigarette,and a cylindrical sleeve 87, such as shown in FIG. 1 except that theaxial air passageways shown in FIG. 1 are no longer provided in anembodiment according to the invention. The heater fixture 39 also caninclude an outer surface or barrel, which preferably also forms theouter housing 31 of the lighter 25, a heater assembly including theheater blades 120, electrically conductive pins or common leads 104A,104B, which serve as common leads for the heater elements of the heaterassembly, and the spacer 49, to which the terminal end hub 110 isfastened.

The heater fixture 39 according to an embodiment of the presentinvention, as shown in FIG. 5, comprises an inner cylindrical sleeve orbarrel 200 concentrically surrounding the heater blades 120 that isprovided with openings through which flow distributing elements 20,shown more clearly in FIG. 5A, are inserted. As shown in FIG. 6, theinner barrel or sleeve 200 is concentrically surrounded by an outerbarrel or sleeve 300, that is also provided with openings 302 and 304,which are preferably placed approximately radially outward from theopenings in the inner barrel or sleeve 200. The outer barrel or sleeve300 preferably forms the outside of the lighter 25, or housing 31 shownin FIG. 1.

It has been found that a primarily transverse or radial air flowrelative to the inserted cigarette results in a more desirable aerosolflow radially inward from the cigarette heater blades. Flow distributingelements 20 shown inserted through side holes in the inner barrel 200 inFIGS. 5, 5A and 6, and shown in detail in FIGS. 3A and 3B, help toensure that air flow entering the inner barrel 200 is distributed evenlyamongst the heater blades within the inner barrel 200.

As shown in FIGS. 3A and 3B, a flow distributor 20 is substantially ahollow, closed-end cylinder with four holes through its wall 20 c nearthe closed end of the cylinder. The holes 30 a, 30 b, 30 c, and 30 d canbe located through the wall 20 c of the flow distributing element nearthe closed end 20 a of flow distributing element 20 and distributedevenly around the circumference of the flow distributing element. In theembodiment shown in FIG. 3B, the holes are located 90 degrees apart,although other alternate configurations are possible and contemplatedwithin the scope of the invention.

As shown in FIGS. 5 and 5A, two flow distributing elements protrudethrough the side walls of the inner barrel or sleeve 200, spaced 180degrees from each other, and extend radially inward toward the interiorof the heater fixture. The openings 30 a, 30 b, 30 c, 30 d arepositioned in the interior of the inner sleeve 200 such that air flowingthrough the flow distributing elements 20 is distributed more uniformlyinside the heater fixture 39. The openings shown in FIG. 3B force air tobe channeled in four different directions as it exits from the flowdistributing element 20 into the interior of the inner sleeve 200.

An outer barrel or sleeve 300 preferably forms the outer housing of thelighter, concentrically surrounds the inner sleeve 200, and is providedwith openings 302, 304 that are preferably positioned radially outwardfrom the location of the flow distributing elements 20 through innersleeve 200. Ambient air on the outside of the outer barrel 300 entersthrough the openings 302, 304 and is directed into the flow distributingelements 20 when a smoker draws upon a cigarette inserted within theheater fixture 39. The outer barrel or sleeve 300 preferably forms theouter housing of the lighter containing the heater fixture 39, such thatopenings 302, 304 open to the outside, ambient air.

The improved air flow that is caused by air entering into the spacearound heater blades 120 after being distributed by passage through theflow distributing element 20 results in an increase in the totaldelivery of aerosol caused by the heating of the cigarette insertedwithin heater blades 120. The improvement in delivery of totalparticulate matter caused by the heating of tobacco in proximity toheater blades 120 has been measured to be approximately 10% greater thanthe total particulate matter delivered by a heater fixture 39 that doesnot include the advantage of the flow distributing elements 20 forbetter air flow distribution to and around the heater blades 120.

Many modifications, substitutions and improvements may be apparent tothe skilled artisan without departing from the spirit and scope of thepresent invention as described in and defined herein and in thefollowing claims. In particular, the number of openings through the flowdistributing element wall is not limited to four and the openings can bedistributed at circumferential positions around the distributing elementother than at 90 degrees. Additionally, although two flow distributingelements 20 are shown at approximately 180 degrees from each otherthrough the wall of inner sleeve 200, the number of flow distributingelements can vary as well as their locations through the wall of theinner sleeve or barrel 200.

While this invention has been described in conjunction with theexemplary embodiments outlined above, many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, the exemplary embodiments of the invention may be madewithout departing from the spirit and scope of the invention.

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 14. A method of operating anelectrically heated cigarette smoking system, comprising: establishingoperative contact between a heater blade and a cigarette; directing airflow adjacent said heater blade by causing the air flow to flow indifferent directions relative to the inserted cigarette before the airis drawn through the cigarette; establishing operative contact between aheater blade and a cigarette in an electrically heated cigarette smokingsystem; and directing air flow in a plurality of directions at alocation adjacent the operatively contacted cigarette.
 15. The methodaccording to claim 14, wherein the air flow is passed through at leastone air flow distributing element having openings in fluid communicationwith a space around the heater blades within the heater.
 16. The methodaccording to claim 15, wherein the openings in the at least one air flowdistributing element direct the air flow at least in oppositedirections.
 17. The method according to claim 16, wherein the openingsdirect the air flow in four different directions.
 18. (canceled)